libsbmlcs.SBMLDocument.setPackageRequired C# (CSharp) Method

        public int setPackageRequired(string package, bool flag)
        {
            int ret = libsbmlPINVOKE.SBMLDocument_setPackageRequired(swigCPtr, package, flag);
            if (libsbmlPINVOKE.SWIGPendingException.Pending) throw libsbmlPINVOKE.SWIGPendingException.Retrieve();
            return ret;
        }

    public static int Main(string[] args)
    {
        // Creates an SBMLNamespaces object with the given SBML level, version
        // package name, package version.
        SBMLNamespaces sbmlns = new SBMLNamespaces(3, 1, "qual", 1);

        // create the document
        SBMLDocument document = new SBMLDocument(sbmlns);

        // mark qual as required
        document.setPackageRequired("qual", true);

        // create the Model
        Model model = document.createModel();

        // create the Compartment
        Compartment compartment = model.createCompartment();
        compartment.setId("c");
        compartment.setConstant(true);

        // Get a QualModelPlugin object plugged in the model object.
        QualModelPlugin mplugin = (QualModelPlugin)(model.getPlugin("qual"));

        // create the QualitativeSpecies
        QualitativeSpecies qs = mplugin.createQualitativeSpecies();
        qs.setId("s1");
        qs.setCompartment("c");
        qs.setConstant(false);
        qs.setInitialLevel(1);
        qs.setMaxLevel(4);
        qs.setName("sss");

        // create the Transition
        Transition t = mplugin.createTransition();
        t.setId("d");
        t.setSBOTerm(1);

        Input i = t.createInput();
        i.setId("RD");
        i.setQualitativeSpecies("s1");
        i.setTransitionEffect(libsbml.INPUT_TRANSITION_EFFECT_NONE);
        i.setSign(libsbml.INPUT_SIGN_NEGATIVE);
        i.setThresholdLevel(2);
        i.setName("aa");

        Output o = t.createOutput();
        o.setId("wd");
        o.setQualitativeSpecies("s1");
        o.setTransitionEffect(libsbml.OUTPUT_TRANSITION_EFFECT_PRODUCTION);
        o.setOutputLevel(2);
        o.setName("aa");

        FunctionTerm ft = t.createFunctionTerm();
        ASTNode math = libsbml.parseL3Formula("geq(s1, 2)");
        ft.setResultLevel(1);
        ft.setMath(math);

        DefaultTerm dt = t.createDefaultTerm();
        dt.setResultLevel(2);

        int result = libsbml.writeSBML(document, "qual_example1.xml");

        if (result == 1)
        {
          Console.WriteLine("Wrote file");
          return 0;
        }
        else
        {
          Console.WriteLine("Failed to write");
          return 1;
        }
    }